The present invention relates to a cutting mechanism for making two cuts through a material. More particularly, it relates to a printing device having anvils that roll against blades to produce cuts of different depths through a tape.
Electronic printing apparatus are known which use a supply of multi-layer tape, housed in a cassette received by the printing apparatus. The multi-layer tape comprises an image receiving layer and a backing layer secured to one another via an adhesive layer. After an image has been printed onto the image receiving layer, the backing layer can be removed allowing the receiving layer to be secured to an object using the adhesive layer. Such printing apparatus include cutting mechanisms for cutting off a portion of the tape for its use as a label after an image has been printed onto the image receiving layer. For this purpose, the cutting mechanism includes a blade for cutting through all of the layers of the multi-layer tape. In some printing apparatus, the cutting mechanism also includes a tab cut blade for cutting through only one of the layers of the multi-layer tape, either the image receiving layer or the backing layer, leaving the other layer intact. For example, in a machine made and sold by Esselte under the trade mark DYMO 6000, a tab cut blade is provided which cuts through the top image receiving layer while leaving the backing layer intact. Such a tab cut allows easy separation of the image receiving layer from the backing layer.
In the DYMO 6000, the tab cut blade is a ceramic blade which is set via insert molding in a tab cut blade holder to a protrusion of about 100 microns. When a tab cut is to be made, force is applied to the blade holder to cause the blade to cut through the image receiving layer of the tape while the tape is supported by a flat anvil surface. Precise control of the amount of blade protruding from the blade holder ensures that a reliable tab cut is made which always cuts through the image receiving layer without cutting the backing layer.
One problem with this arrangement is that it requires the application of significant force, particularly when cutting wide tapes. These printing apparatus operate with tapes having widths of 6 mm, 12 mm and 19 mm. When performing a tab cut on a 19 mm tape, the force required can be as much as 80 to 100 N. It is very difficult for smaller printing apparatus to apply the high loads that the cutting operation requires.
A cutting mechanism which overcomes this difficulty is described in our copending U.S. application Ser. No. 08/556,885. In the disclosed cutting mechanism, an anvil is mounted for rolling motion relative to a cutting blade. To perform a cut, the anvil is rolled along the blade, progressively cutting across the tape. Thus, the actuation force required in this operation is much lower than if the entire width of tape were to be cut simultaneously.
In the ""885 application, in which the rolling anvil is used to implement a tab cut, a full cut is implemented by a separate cutting mechanism, mechanically connected to the rolling anvil. This separate mechanism forces the entire cutting edge of a blade against a stationary anvil at once, and hence requires a large force to be applied during the cut.
As described in U.S. Pat. No. 5,458,423, a mechanism that produces a full cut can be disabled so that only a tab cutting mechanism operates. This allows a string of labels to be produced, wherein the labels are secured to a common backing strip and separated by tab cuts. The disabling of the full cutting mechanism in this reference, however, must be done manually. From a practical point of view, this means that the machine must be located accessibly to a user.
It is desirable to provide for remote printing devices which can operate by communication with host PCs or other desktop label formulation apparatus. Such printing and cutting devices can be controlled remotely from the printing apparatus itself.
The present invention relates to a cutting mechanism for cutting a material, such as a multilayer tape. The mechanism has first and second cutters respectively with first and second opposing blade and anvil components. Either the first anvil or blade component and either the second anvil or blade component are rollers that are mounted for rolling along the anvil or blade component opposed to each roller. This rolling motion progressively biases and cuts the material with the first blade component. Likewise, one of the second anvil and blade components is in the form of a second roller mounted for rolling along the other for progressively biasing and cutting the tape with the second blade component. Preferably, the first blade and anvil components are arranged to cooperatively cut through all layers and the entire thickness of the multi-layer tapes and the second blade and anvil components are arranged to cooperatively cut through one or more layers of the multi-layer tape, while leaving at least one layer and a portion of the thickness of the tape intact.
The rollers are preferably the anvil components, and are rotatably mounted on a carriage that is movable parallel to the blades. As the carriage moves, the anvil components roll over the blades, widthwise with respect to the tape, thus cutting the tape.
The resulting cutting -mechanism can make a tab cut and a full cut through a multi-layer tape at locations spaced along the length of the tape. The cutting mechanism is particularly useful in printing devices of the type hereinbefore described.
The present invention can also provides a printing device with the described cutting mechanism. This printing device can be operated from an input device such as a keyboard, in which a user may enter information such as characters to be printed, length of label, and format of label, and may select other modes for the printer to operate.
The printing device preferably also includes a printing mechanism comprising a printhead and platen for performing printing operations.
In one type of suitable printing device, an multilayer image-receiving tape is passed in overlap with a thermal transfer ribbon through the printing mechanism. The tape is fed through the printing location by a motor arranged to drive the platen or a set of feed rollers to pull the tape past the printing location. The printing device preferably has a controller in the form of a microprocessor which controls the timing and positioning of printing with respect to the movement of the tape, according to the data entered by the user. The thermal printhead has a column of printing elements so that an image is printed on the tape column by column as the tape moves past the printing mechanism.
In normal operations, the tape is printed upon, and tab and full cuts are made to produce a label. Alternatively, tab cuts can be made at spaced locations along the length of the tape to produce numerous labels which can then be removed from a common backing. To achieve this, one of the cutters is selectively disengageable, for example by increasing the spacing between an opposing blade and anvil, so that the cutter will not produce a cut in its disengaged state. Preferably, this cutter can be engaged and disengaged by moving the rolling anvils passed predetermined positions.
Preferably, each anvil component has a circumferential slot aligned with its opposing blade component to prevent direct contact between the blade component and the surface of the anvil component. This arrangement reduces damage and wear of the cutters. The amount by which each blade component protrudes from a blade holder can be less accurately controlled than when used with an anvil component that lacks the slot. This relaxes the tolerances on production blade straightness. With these slots, a common blade holder can be used to hold two blade components protruding therefrom by different amounts, one protruding sufficiently to produce a tab cut, and the other to produce a full cut through the thickness of the tape.
The input device, or other user interface, does not need to form part of a common housing with the printing mechanism and cutting mechanism, but may be disposed remotely therefrom. A remote arrangement allows the user to control the cutting mechanism, without the needing to intervene manually.
The invention also provides a lead screw with a cam on its end. The lead screw is received through an internally threaded bore in the carriage. A switch, resiliently biased against the cam produces electrical pulses, and a counter of the controller measures the position of the carriage.
This invention enables a user to implement a variety of label options, such as printing multiple copies of labels, wherein copies can be counted more simply than with earlier printing devices.